The present invention relates to a wheel which comprises a passive mechanism adapted to vary its outer diameter according to the drive torque applied to said wheel.
The present invention is applicable, in particular, to vehicles or wheel-based mechanisms in general.
It is known that vehicles fitted with tire wheels and intended for off-road use or for use on uneven surfaces can be hindered by obstacles or rough terrain.
Normally such vehicles are equipped with an all-wheel-drive system, but for vehicles having many wheels, or when an all-wheel-drive system cannot be installed in a vehicle even if it does not have many wheels, this solution becomes unacceptable in terms of costs and technical complexity.
It is known that, for such wheeled vehicles, if an obstacle is higher than the wheel axis, that obstacle cannot be overcome because the wheel will stop against it.
It is therefore appropriate, for such vehicles, to adopt large-diameter wheels, so that most obstacles, like rocks or steps, can be overcome.
It is also known that medium and large-diameter wheels, such as, for example, those of armoured and/or amphibious vehicles, take up much space when stored and are difficult to handle, e.g. when they must be replaced, thus causing both logistic and operational problems.
It is also known that, in the field of robotized vehicles, vehicles are known which are suitable for detecting, defusing and deflagrating explosive devices and which are used in missions normally identified by the English acronyms EOD, IEDD and NBC.
In such types of missions it is necessary that the vehicle in use is as small and as easy to handle as possible, so that it can reach narrow and impervious places and make observations underneath other vehicles for the purpose of finding out any dangerous materials, e.g. explosive materials.
In most missions wherein they are employed, these robotized vehicles are forced to move within unstructured and often rough environments that include many obstacles.
Quite often, such obstacles cannot be overcome because the wheels of said vehicles have a small diameter and are easily prone to getting stuck, thereby causing the vehicle to stall.